34 FRESn-WATER A L G vE OF THE UNITED STATES. 



European S. cakicola, from wliicli it differs somewhat, however, in having its hete' 

 rocysts both terminal and among tlic cells, and also somewhat in their size. 



I¥. calidariiim, Wood. 



N. thallo maxinio, indefinite expanse, aut membranaceo-coriaceo vel raembranaceo-g-elatinoso 

 vel mcnibraiiaceo, aut Irote virdi vel sordide olivaceo-viridi vel olivaceo-brunneo, irregulariter 

 profunde laciniato-sinuato, ultimo eleganter laciniato; tricliomatibus intequalibus, interdum 

 flexuoso-curvatis, plerumque subrectis et arete conjunctis, in forniis duabus occurrentibus : 

 forma altera parva, viridi, artieulis eylindncis, cum cellulis perdurantibus hie illic interjectis, 

 vaginis interdum obsoletis, sa;pius diffluentibus; forma altera maxima, artieulis globosls vel 

 oblongis, aurautiaco-brunnca, cellulis perdurantibus ab artieulis ceteris baud diversis. 



Biarn.—Formoi prima; articuli maxiini jijj^^ unc. ; cellule perdurantis ^^jVu unc. FornitB 

 secundre articuli long, s^^w to tsucu ""c., hit. jj^Vu to ^^\^, articuli globosi ^gVuto ^^Vir ""c. 

 Syn. — N. calidariuni, Wood, American Journal of Science and Arts, 1869. 

 Hab. — "Benton Springs, Owen's Valley, California" (Mrs. Partz). 



Thallus very large, indefinitely e.xpanded, either membrano-coriaceous or membrano-gelatinous 

 or membranaceous, either bright green or dirty olive-green or olive-brown, irregularly pro- 

 foundly lacinlately sinuate, finally elegantly laciniate ; filaments unequal, sometimes fiexu- 

 ously curved, but mostly straightish and closely conjoined, occurring in two forms ; the 

 one small, green, with cylindrical joints, the heterocysts scattered here and there, the sheaths 

 sometimes absent, often diffluent; the other form very large, with globose or oblong articles, 

 orange-brown, the heterocysts not different from the other cells. 



Remarks. — Numerous specimens of this species were received from Mrs. Partz, 

 who collected them in Benton's Spring, a thermal water situated in the extreme 

 northern point of Owen's Valley, California, sixty miles southwest from the town 

 of xVurora. The following extract from a letter of Mrs. Partz describes the place 

 and mode of their growth more minutely. 



" I send you a few samples of the singular vegetation developed in the hot springs 

 of our valley. These springs rise from the earth in an area of about eighty square 

 feet, which forms a basin or pond that ponrs its hot Avaters into a narrow creek. 

 In the basin are produced the first forms, partly at a temperature of 12-4° — 135° 

 Fahr. Gradually in the creek and to a distance of 100 yards from the springs are 

 developed, at a temperature of 110° — 120° Fahr., the Algfe, some growing to a 

 length of over two feet, and looking like biniches of waving hair of the most beau- 

 tiful green. Below 100° Fahr., these plants cease to grow, and give way to a slimy 

 fungus growth, though likewise of a beautiful green, which, finally, as the tempera- 

 ture of the water decreases, also disappears. They are very difficult to preserve, 

 being of so soft and pulpy a nature as not to bear the least handling, and must 

 be carried in their native liot water to tlie house, very few at a time, and floated 

 upon paper. After being taken from the water and allowed to cool they become 

 a black pulpy mass. But more strange than the vegetable are the animal organ- 

 izations, whose germs, probably througli modifications of successive generations, 

 have finally become indigenous to these strange precincts. Mr. Partz and myself 

 saw in the clear water of the basin a very sprightly spider-like creature running 

 nimbly over the ground, where the water was 124° Fahr., and on another occasion 

 dipped out two tiny red worms." 



